Human cone photopigment kinetics will be investigated with color matching (a non-invasive psychophysical technique) and flicker electroretinography (an electrophysiological technique. Color matches depend on cone photopigment density, as well as spectral sensitivity. At any level of retinal illuminance photopigment density is maintained by a dynamic balance between the processes of photopigment bleaching (due to the absorbtion of light) and photopigment regeneration (due to biochemical reactions taking place in both the photoreceptors and the retinal pigment epithelium). As illuminance increases, photopigment density decrases due to bleaching. Changes in color matches with illuminance will yield a quantitative measure of the function of the outer retina. Additionally this data will test current theories concerning the cone photopigments. The recovery of the flicker ERG following large field bleaches will be used as a measure of photopigment regeneration. The stimulus will be a 30 degree flickering field. The ERG will be measured using a vector voltmeter. Time constants for the regeneration of the photopigments will be calculated. The contribution of various retinal factors to photopigment regeneration will be studied by testing patients recovering from retinal detachments, patients with diabetic retinopathy, and patients with diseases in which kinetic factors have previously been implicated. A comparison of electrophy siologically determined recovery rates and psychophysical estimates of photopigment kinetics will be made. These comparisons will allow us to judge the potential of these techniques as fast, noninvasive probes of the status of the outer retina. The existence of such probes could be useful in the clinical evaluation of the retina.